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ta có :\(9^{31}=\left(3^2\right)^{31}=3^{62}\)
\(27^{21}=\left(3^3\right)^{21}=3^{63}\)
vì \(3^{62}< 3^{63}\)
nên \(9^{31}< 27^{21}\)
a, 920=(92)10=8110
vì 81 <9999 suy ra 920<999910
b, vì 3>2 suy ra 321>221
Ta có:
7215 = (23.32)15 = 245.330
321.969 = 321.(25.3)9 = 321.245.39 = 330.245
=> 7215 = 321.969
b/ Ta có: 291>290=(25)18=3218>2518=(52)18=536>535 => 291>535
c/ Ta có: 2225=(23)75=875
3150=(32)75=975
Vì 875<975 nên 2225<3150
a)Ta có: 2^27=(2^3)^9=8^9
3^18=(3^2)^9=9^9
Vì 8^9 <9^9
2^27<3^18
d)Ta có :27^7=(3^3)^7=3^21
9^12=(3^2)^12=3^24
Vì 3^21<3^24
27^7<9^12
Xin lỗi bạn mình chỉ làm đc câu 2 thuiiii :((((((
b) Ta có:
\(555^{20}=111^{20}.5^{20}=111^{20}.\left(5^2\right)^{10}=111^{20}.25^{10}\)
\(222^{50}=111^{50}.2^{50}=111^{50}.\left(2^5\right)^{10}=111^{50}.32^{10}\)
Vì \(111^{50}.32^{10}>111^{20}.25^{10}\)nên \(222^{50}>555^{20}\)
bài 2
làm câu B;C nha
B)
\(27^3=\left(3^3\right)^3=3^9\)
\(9^5=\left(3^2\right)^5=3^{10}\)
vì \(10>9\)
\(=>9^5>27^3\)
C)
\(\left(\frac{1}{8}\right)^6=\left(\frac{1}{2^3}\right)^6=\frac{1^6}{2^{18}}=\frac{1}{2^{18}}\)
\(\left(\frac{1}{32}\right)^4=\left(\frac{1}{2^5}\right)^4=\frac{1^4}{2^{20}}=\frac{1}{2^{20}}\)
vì \(2^{18}< 2^{20}\)
\(=>\frac{1}{2^{18}}>\frac{1}{2^{20}}\)
\(=>\left(\frac{1}{8}\right)^6>\left(\frac{1}{32}\right)^4\)
\(\text{A.}\frac{32^3.9^5}{8^3.6^6}=\frac{\left(2^5\right)^3.\left(3^2\right)^5}{\left(2^3\right)^3.\left(2.3\right)^6}=\frac{2^{15}.3^{10}}{2^9.2^6.3^6}=\frac{3^{10}}{3^6}=3^4=81\)
\(\text{B.}\frac{\left(5^5-5^4\right)^3}{50^6}=\frac{2500^3}{50^6}=\frac{\left(50^2\right)^3}{50^6}=\frac{50^6}{50^6}=1\)
Bài 2:
\(\text{A.Ta có:}\)
\(5^6=\left(5^3\right)^2=125^2\)
\(\left(-2\right)^{14}=2^{14}=\left(2^7\right)^2=128^2\)
Vì \(125< 128\)
\(\Rightarrow125^2< 128^2\)
\(\Rightarrow5^6< \left(-2\right)^{14}\)
\(\text{B.Ta có:}\)
\(9^5=\left(3^2\right)^5=3^{10}\)
\(27^3=\left(3^3\right)^3=3^9\)
Vì \(9< 10\)
\(\Rightarrow3^9< 3^{10}\)
\(\Rightarrow27^3< 9^5\)
\(\text{C.Ta có:}\)
\(\left(\frac{1}{8}\right)^6=\left[\left(\frac{1}{2}\right)^3\right]^6=\left(\frac{1}{2}\right)^{18}\)
\(\left(\frac{1}{32}\right)^4=\left[\left(\frac{1}{2}\right)^5\right]^4=\left(\frac{1}{2}\right)^{20}\)
Vì \(18< 20\)
\(\Rightarrow\left(\frac{1}{2}\right)^{18}< \left(\frac{1}{2}\right)^{20}\)
\(\Rightarrow\left(\frac{1}{8}\right)^6< \left(\frac{1}{32}\right)^4\)
Ta có 921=(32)21=342
3.2714=3.(33)14=3.342=343
Vì 42<43.
Nên 342<343.
Vậy 921 < 3.2714